Buoyant, Variably Buoyant and Non-Buoyant Foil Structures for Marine Vessels and Watercraft

ABSTRACT

A watercraft including a side-hull extending downwardly from each side of a hull of the watercraft. A foil extends downwardly and inwardly from each side-hull.

This application claims priority to Canadian Patent Application No. 2,835,902, entitled BUOYANT, VARIABLY BUOYANT AND NON-BUOYANT FOIL STRUCTURES FOR MARINE VESSELS AND WATERCRAFT and filed on Nov. 28, 2013, the entire contents of which are hereby incorporated by reference.

FIELD

The present invention relates to buoyant, variably buoyant and non-buoyant foil structures for marine vessels and watercraft, and more particularly, relates to buoyant, variably buoyant and non-buoyant foil structures for marine vessels and watercraft that provide increased operational stability.

BACKGROUND

Conventional watercraft (which term “watercraft” will be understood hereinafter to include all manner of marine vessels, including ships, boats, seaplanes, and personal watercraft adapted for use in either commercial, pleasure, military, shipping or other context, whether powered by engine, wind or otherwise), may experience undesirable pitching and rolling during normal operation under wavy or unsettled marine conditions. For example, the buoyancy of the watercraft in motion may cause the watercraft to pitch in an undesirable and perhaps dangerous manner when encountering a sufficiently large wave. For example, upon transversing a large wave, the buoyant hull of the watercraft may briefly raise the bow of the watercraft, and thereafter the stern of the watercraft, as the watercraft passes partially over and partially through the large wave. When the wave is insubstantial, or where the watercraft is of very substantial mass relative to the size of the wave, the wave may have little effect on the pitch or roll of the watercraft. In other circumstances, however, a substantial wave may significantly and negatively effect the operation of the watercraft, and may place the watercraft, its cargo and crew at significant risk of harm or loss.

It is desirable to provide a watercraft with increased stability, and with reduced pitching action when encountering waves, particularly waves that would otherwise significantly and negatively affect the operation of the watercraft.

It is also desirable to provide a watercraft with increased stability and with reduced rolling action when encountering waves, particularly waves that would otherwise significantly and negatively affect the operation of the watercraft.

SUMMARY

Accordingly, one object of the present invention is to provide a watercraft with increased stability, and with reduced pitching action when encountering waves, particularly waves that would otherwise significantly and negatively affect the operation of the watercraft.

Another object of the present invention is to provide a watercraft with increased stability and with reduced rolling action when encountering waves, particularly waves that would otherwise significantly and negatively affect the operation of the watercraft.

According to one aspect of the present invention, there is provided a watercraft. A side-hull extends downwardly from each side of a hull of the watercraft. A foil extends downwardly and inwardly from each side-hull.

According to another aspect of the present invention, there is provided a method for operating a watercraft. The watercraft comprises a hull having a side-hull extending downwardly from each side of the hull. A foil extends downwardly and inwardly from each side-hull. The watercraft is propelled to a speed sufficient for planing such that a substantial portion of lift acting on the watercraft is provided through contact between a portion of a bottom surface of each foil and the water.

An advantage of the present invention is that it provides a watercraft with increased stability, and with reduced pitching action when encountering waves, particularly waves that would otherwise significantly and negatively affect the operation of the watercraft.

A further advantage of the present invention is that it provides a watercraft with increased stability and with reduced rolling action when encountering waves, particularly waves that would otherwise significantly and negatively affect the operation of the watercraft.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the present invention is described below with reference to the accompanying drawings, in which:

FIGS. 1A, 1B and 1C are a side view, a front view and a bottom view, respectively, of one embodiment of the present invention positioned ‘at rest’ in the water;

FIGS. 2A, 2B and 2C are a side view, a front view and a bottom view, respectively, of the embodiment of the present invention illustrated in FIGS. 1A, 1B and 1C positioned “on plane”, in the water;

FIGS. 3A, 3B, 3C, 3D, 3E, 3F, 3G and 3H are side and front views of the embodiment of the present invention illustrated in FIG. 1A, on plane, passing through a wave;

FIG. 3I is a view of the leading edge of the foil having pierced through the leading edge of a wave;

FIGS. 4A, 4B and 4C are a side view, a front view and a bottom view, respectively, of an embodiment of the present invention having non-buoyant foils and side-hulls, positioned ‘at rest’ in the water;

FIGS. 4D, 4E and 4F are a side view, a front view and a bottom view, respectively, of the embodiment of the present invention illustrated in FIGS. 4A, 4B and 4C positioned “on plane”, in the water;

FIGS. 5A, 5B and 5C are a side view, a front view and a bottom view, respectively, of an embodiment of the present invention having a substantially flat wet deck, positioned ‘at rest’ in the water;

FIGS. 5D, 5E and 5F are a side view, a front view and a bottom view, respectively, of the embodiment of the present invention illustrated in FIGS. 5A, 5B and 5C positioned “on plane”, in the water;

FIGS. 6A, 6B and 6C are a side view, a front view and a bottom view, respectively, of an embodiment of the present invention having a deep-v type centre hull positioned between vertically shortened side-hulls, positioned ‘at rest’ in the water;

FIGS. 6D, 6E and 6F are a side view, a front view and a bottom view, respectively, of the embodiment of the present invention illustrated in FIGS. 6A, 6B and 6C positioned “on plane”, in the water;

FIGS. 7A, 7B and 7C are a side view, a front view and a bottom view, respectively, of an embodiment of the present invention having a deep-v type centre hull positioned between vertically shortened side-hulls with the side-hulls and foils having truncated length, positioned ‘at rest’ in the water; and

FIGS. 7D, 7E and 7F are a side view, a front view and a bottom view, respectively, of the embodiment of the present invention illustrated in FIGS. 7A, 7B and 7C positioned “on plane”, in the water.

DETAILED DESCRIPTION

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, certain methods and materials are now described.

In an embodiment of the present invention, as illustrated in FIGS. 1A, 1B and 1C, a watercraft generally shown as 10 is provided, having overall dimensions of 40 ft. long by 10.5 ft. wide by 7.5 ft. high (from the surface of the boat deck to the bottom edge of fins 160). In the embodiment of the invention depicted in FIGS. 1A, 1B and 1C, the watercraft 10 has the hull 20, cabin 25, side-hulls 30 on both sides thereof, and extending downwardly in a substantially vertical orientation, and from each of which side-hulls 30 depend downwardly and inwardly foils 40. In this embodiment of the invention, the side-hulls and foils are watertight, substantially hollow, and by means of spaced strengthening rib members positioned within the side-hulls 30 and foils 40, are rigidly and securely engaged with the watercraft 10 and form part of the hull 20 of the watercraft 10, it being understood that alternative techniques known to a person skilled in the art may alternatively be utilized to rigidly and securely engage the side-hulls and foils to form part of the watercraft 10, including, for example, with the components being made of a composite material such as fiberglass, manufactured and assembled using conventional molding and bonding techniques.

In this embodiment of the watercraft 10, each of the foils 40 have an upper surface 50, and a lower surface 60, that extend substantially along the upper and lower sides of each of the foils 40, respectively. Each foil 40 has a leading edge 65 and an upper leading surface 70, and lower leading surface 80, extending rearwardly from leading edge 65 that smoothly transition into the upper surface 50 and a lower surface 60 respectively.

Optionally, an extension of the upper leading surface 70 and the lower leading surface 80 from the leading edge 65 increases with decreasing distance to the side-hulls 30.

The watercraft of the present invention optionally has a wet deck 90 of varying sizes, shapes and volumes ranging from a flat surface with the least volume to a deep-v with the greatest volume, including shapes such as lateral ‘steps’, known as a ‘stepped-hull’ and other monohull designs/shapes known to someone skilled in the art, positioned on a lower surface of the hull as more fully described herein.

In this embodiment of the invention, the watercraft 10, when stationary or while operating at below planing speed, is as illustrated in FIGS. 1A, 1B and 1C positioned in the water such that the wet deck 90 is above the surface of the water 100, the buoyant side-hulls 30 and foils 40 maintaining the wet deck 90 and upper hull above the surface of the water 100.

In one embodiment of the present invention, short vertical fins 160 extend downwardly from the lower edges of the foils 40 to provide additional directional stability particularly when the watercraft is operating at planing speeds.

Optionally, the length of the side-hulls 30 and the foils 40 is truncated to some extent depending, for example, on the operational conditions the watercraft 10 is designed for.

In Operation in Wave-Less or Small Wave Conditions

As the watercraft 10 velocity is increased, the watercraft 10 begins to plane as illustrated in FIGS. 2A, 2B and 2C, that is, the watercraft is angled 63 upwardly, and is partially elevated (relative to comparable operation of the watercraft at sub-planing velocity), the contact between the watercraft 10 and the water being substantially limited to the planing surface 62 of a length of the lower surface of each foil proximate the stern of the watercraft, as illustrated in FIG. 2C. Lines 170, 172, 174 and 176 indicate contact lines with the water surface during operation of the watercraft 10 while planning with: line 170 indicating the contact line of the lower surface 60 of the foil 40 when ‘on plane’; line 172 indicating the contact line of the fin 160 and the upper surface 70 of the foil 40 when ‘on plane’; line 174 indicating the contact line of the fore portion of the foils 40 when ‘on plane’; and line 176 indicating the contact line of the aft portion of the foils 40 when ‘on plane’.

In Operation in Substantial Waves

As illustrated in FIG. 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H and 3I, as the planing watercraft 10 approaches a substantial wave 120, the leading edge of the foil 65 pierces the leading edge 122 of wave 120 as illustrated in FIG. 3C, 3D and 3I and cuts through an upper portion 124 of wave 120 as illustrated in FIG. 3G, the upper portion 124 of the wave 120 being directed above the foil by the leading edge of the foil 65 and the upper leading surface 70 thereof so that the water forming the upper portion of the wave passes through the tunnel 140 (the tunnel 140 being that passage formed by the wet deck 90, side-hulls 30 and foils 40 as illustrated in FIGS. 3B, 3D, 3F). In this way, the water from the upper portion 124 of the wave 120 passes through the tunnel 140, exiting therefrom at the stern of the watercraft 10 with reduced overall pitching effect on the watercraft 10, as illustrated in FIGS. 3G and 3H. The volume of water from the top of the wave passes over the upper surface 50 of the foil 40 and is counteracting the lift from the foil 40, and as this volume of water continues down the tunnel the buoyancy of the foils 40 and the side-hulls 30 being immersed deeper in the water lifts the watercraft 10 up but with substantially reduced pitching. Furthermore, the volume of water flowing over the upper surface 50 of the foils 40 aft counteract the buoyant force of the watercraft 10 acting at the stern and substantially prevent the same from rising up as the watercraft 10 exits the wave, thus the watercraft 10 maintains a substantially level orientation. Preventing the stern from pitching up and consequently the bow from pitching down when passing through a wave enables the watercraft 10 to penetrate the following wave at a substantially correct angle and to repeat the process at substantially level orientation.

Simultaneously, as this buoyant/lifting action is occurring, there is a hydraulic action of a portion of the volume of water on the upper surface 50 of the foils 40 evacuating down through the gap 165 between the foils 40, dampening the vertical movement and ‘distributing’ it along the length of the gap 165 and tunnel 140. A truncated lower portion of the wave may be directed beneath the foil by the leading edge of the foil 65 and the lower leading surface 80 thereof so that the water forming the truncated lower portion 126 of the wave 120 passes along the lower surface of the foil, this truncated lower portion 126 of the wave 120 is of reduced height relative to the full wave itself and therefor has reduced lifting impact on the lower surface of the foils and reduced lifting impact, reduced upward acceleration and reduced lift of the watercraft 10, and reduced likelihood of negative impact of the watercraft's crew, personnel, cargo and equipment.

In situations when waves are encountered that are large enough to cause the bow of the watercraft 10 to pitch up, the gap 165 between the foils 40 provides a dampening effect and reduces the likelihood of the watercraft 10 getting airborne. If the watercraft gets airborne the gap 165 between the foils 40 acts again as a dampener reducing the overall effect of the slam when the watercraft enters the water again.

Increased pitch stability is also experienced at non-planing speed or when transitioning the watercraft from non-planing to planing. Here, the weight of the water passed through the tunnel 140 and acting on the upper surfaces 50 of the foils 40 reduces the lifting impact of the wave resulting in a reduced upward acceleration and reduced lift of the watercraft 10. The gap 165 between the foils 40 allows water to flow between the space above the foils 40 to the space below the foils 40 resulting in a hydraulic dampening effect along the length of the gap 165.

The weight of the water passed through the tunnel 140 and acting on the upper surfaces 50 of the foils 40 also dampens roll movement of the watercraft 10 at non-planing speed or when transitioning the watercraft from non-planing to planing. For example, if the watercraft 10 is tilting towards starboard due to side impact of a wave, the weight of the water acting on the upper surface 50 of the foil 40 on the port side of the watercraft 10 is reducing the tilting effect of the wave impact.

Roll movement of the watercraft 10 is also dampened when planing For example, if the watercraft 10 is tilting towards starboard due to side impact of a wave, the size of the planing surface 62 on the starboard foil is greater than the size of the planing surface 62 on the port foil, increasing lift on the starboard side counteracting the roll movement.

When inducing a turn, the watercraft 10 tends to sideslip, i.e. the line of thrust and the center of gravity are offset. Due to the resulting change in water flow the outboard foil 40 tends to raise up caused by increased lift acting on the lower surface 60 of the outboard foil 40. Simultaneously, due to this change in water flow the inboard foil 40 tends to lower into the water due to the side slipping action of the watercraft 10. Consequently, there is more water flowing over the upper surface 50 of the inboard foil 40 driving it deeper into the water until it reaches equilibrium due to increased buoyancy of the inboard foil 40. When the thrust vector is returned to be in line with the watercraft 10, the same returns to its original level equilibrium.

The gap 165 between the foils 40 allows water to flow from the space above the foils 40 to the space below the foils 40, generally providing a dampening effect on pitch and roll movement of the watercraft 10.

Non-Buoyant Embodiment

In one embodiment of the invention, as illustrated in FIGS. 4A, 4B, 4C, 4D, 4E and 4F, the foils 40 and/or side-hulls 30 are either substantially neutrally buoyant, or alternatively, non-buoyant, the overall watercraft 10 afloat at rest, as illustrated in FIGS. 4A, 4B and 4C, in consequence of the buoyant effect of the overall configuration of the hull of the watercraft 10, including, for example, the wet deck. By way of example only, substantially neutrally buoyant, or alternatively, non-buoyant foils 40 and/or side-hulls 30 may be used on either planing or non-planing watercraft.

In the case of planing watercraft 10, substantially neutrally buoyant, or alternatively, non-buoyant foils 40 and/or side-hulls 30 may be used, for example, where buoyancy of the foils 40 and/or side-hulls 30 is undesirable or unnecessary, or where the selected buoyant materials or internal construction of the foils 40 and/or side-hulls 30 may otherwise result in a structurally less robust water craft. By way of example, substantially neutrally buoyant, or alternatively, non-buoyant foils 40 and/or side-hulls 30 may be used on buoyant personal watercraft, pontoon boats, pleasure boats, off-shore fishing boats and other rugged or hard-use watercraft that may, for example, from time to time, come into contact with the sea or lake bottom, or shore may benefit from non-buoyant foils 40 and/or side-hulls 30, and in one embodiment of the present invention, truncated foils and side-hulls may alternatively be used.

In the case of non-planing watercraft 10, substantially neutrally buoyant, or alternatively, non-buoyant foils 40 and/or side-hulls 30 may be used, for example, where the buoyancy of the foils 40 and/or side-hulls 30 is relatively insignificant when compared to the overall mass of the watercraft, such as in the case of a large cargo ship.

Operation of Non-Buoyant Embodiment

In this embodiment of the invention, the watercraft, when stationary or while operating at below planing speed is as illustrated in FIGS. 4A, 4B and 4C positioned in the water such that the wet deck is in contact with or fully or partially submerged in the water. As the velocity of the watercraft 10 is increased, the watercraft 10 begins to plane, that is, the watercraft angles 63 upwardly, and is partially elevated, the contact between the vessel and the water being substantially limited to the planing surface 62 of a length of the lower surface of each foil proximate the stern of the watercraft, as illustrated in FIGS. 4D, 4E and 4F.

Variably Buoyant Embodiment

In one embodiment of the invention, the foils 40 and/or side-hulls 30, (or tanks or cavities within the foils 40 and/or side-hulls 30), may be variably filled, or variably partially filled with ballast water, thereby variably fully or partially reducing the overall buoyant effect of the foils and/or side-hulls on the watercraft as a whole, or alternatively may be variably emptied, or variably partially emptied of ballast water, thereby variably increasing the buoyant effect of the foils and/or side-hulls on the watercraft as a whole. The foils 40 and/or side-hulls 30, (or tanks or cavities within the foils 40 and/or side-hulls 30) may be filled or emptied by one or more pumps that may be used in a conventional and controlled manner by the watercraft operator in such manner as to precisely control the volume of water within the foils 40 and/or side-hulls 30, (or tanks or cavities within the foils 40 and/or side-hulls 30).

Alternatively the foils, side-hulls, tanks or cavities may be filled/drained passively, by providing carefully positioned openings in the surfaces of the foils or side-hulls such that the openings are positioned below the water surface when the vessel comes to rest for filling and above the water surface when the vessel transitions to a planning mode for draining Further alternatively, the openings are provided with a valve mechanism enabling the operator to control filling/draining of the tanks For example, the operator chooses to keep some water contained within the foils and/or side-hulls during planning

Operation of Variably Buoyant Embodiment

While the watercraft 10 is at rest, increased pitch stability may be desirable. In this circumstance, the watercraft 10 may be lowered relative to the surface of the water so that the wet deck is in contact with and/or partially submerged in the water, as illustrated in FIGS. 4A, 4B and 4C, thereby providing buoyant support for the watercraft 10 along that length of the wet deck that is in contact with and/or partially submerged in the water, thereby increasing the pitch and roll stability of the watercraft 10. For example, the increased stability of the watercraft 10 at rest allows for loads to be distributed over the watercraft 10 with the same reacting less sensitively to the changes of the load distribution. When the increased pitch stability is no longer beneficial, or where reduced overall watercraft mass (including ballast water) is desirable (for example, when planing, or when transitioning the watercraft from non-planing to planing), the ballast water may be variably and fully emptied from the foils 40 and/or side-hulls 30 (or tanks or cavities within the foils 40 and/or side-hulls 30). As the watercraft 10 velocity is increased, the watercraft 10 begins to plane, that is, the watercraft angles 63 upwardly, and is partially elevated, the contact between the vessel and the water being substantially limited to the planing surface 62 of a length of the lower surface of each foil proximate the stern of the watercraft, as illustrated in FIGS. 4D, 4E and 4F.

Pontoon-Type Embodiment

In one embodiment of the invention, as illustrated in FIGS. 5A, 5B, 5C, 5D, 5E, and 5F, the watercraft 10 comprises hull 20 having a substantially flat wet deck 90, providing a pontoon-type watercraft 10 operated, for example, from helm 180 disposed on the hull 20. Side-hulls 30 extend on both sides of the hull 20 downwardly in a substantially vertical orientation, and from each of which side-hulls 30 depend downwardly and inwardly foils 40. Operation of the pontoon-type watercraft 10 is similar to the operation of the watercraft illustrated in FIGS. 1A, 1B, 1C, 2A, 2B and 2C hereinabove with FIGS. 5A, 5B and 5C depicting the watercraft 10 at rest or non-planing mode and FIGS. 5D, 5E and 5F depicting the watercraft 10 in planing mode. It is understood, that the side-hulls 30 may be provided having various shapes such as, for example, cylindrical shapes, box beam shapes, or monohull shapes. Furthermore, the side-hulls 30 may be buoyant or variably- buoyant, while the foils 40 may be buoyant, variably-buoyant, or non-buoyant.

Shortened Side-Hull Embodiment

In one embodiment of the invention, as illustrated in FIGS. 6A, 6B, 6C, 6D, 6E and 6F, the side-hulls 30 are shortened in relation to the center hull 20 compared to the embodiments described hereinabove. Here, the foils 40 project downward to approximately a same horizontal plane as the bottom of the center hull 20. The side-hulls 30 and the foils 40 may be buoyant, non-buoyant, or variable buoyant.

Operation of Shortened Side-Hull Embodiment

In this embodiment of the invention, the watercraft 10, when stationary or while operating at below planing speed is as illustrated in FIGS. 6A, 6B and 6C positioned in the water such that the wet deck is in contact with or fully or partially submerged in the water. As the velocity of the watercraft 10 is increased, the watercraft 10 begins to plane, that is, the watercraft angles 63 upwardly, and is partially elevated, the contact between the vessel and the water being substantially limited to the planing surface 62 of a length of the lower surface of each foil proximate the stern of the watercraft, as illustrated in FIGS. 6D, 6E and 6F. It is understood, that the deep-v centre hull, as illustrated in FIGS. 6A, 6B, 6C, 6D, 6E and 6F, reduces the volume of the tunnel 140 compared to the embodiment illustrated in FIGS. 1A, 1B, 1C, 2A, 2B, and 2C.

Truncated Foils and Shortened Side-Hull Embodiment

As illustrated in FIGS. 7A, 7B, 7C, 7D, 7E and 7F, foils and shortened side-hulls 30 of truncated length are positioned proximate the stern of watercraft 10.

The present invention has been described herein with regard to certain embodiments. However, it will be obvious to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as described herein. 

What is claimed is:
 1. A watercraft comprising: a hull; a side-hull extending downwardly from each side of the hull; and a foil extending downwardly and inwardly from each side-hull.
 2. A method for operating a watercraft comprising: providing a hull; providing a side-hull extending downwardly from each side of the hull; providing a foil extending downwardly and inwardly from each side-hull; and propelling the watercraft to a speed sufficient for planing such that a substantial portion of lift acting on the watercraft is provided through contact between a portion of a bottom surface of each foil and the water. 